Saturday 11 October 2008 19.01 EDT
First published on Saturday 11 October 2008 19.01 EDT

The idea of writing in a room of one's own never made sense to Steve Toltz. He can't, he says, sit in any place to work longer than two hours: 'I have to get out, move on.' It took him five years to write his Booker-nominated debut novel, A Fraction of the Whole, and those years were divided into two-hour increments. When he was in Sydney he would write on the beach at Bondi, where he lives, or in cafes, libraries, cemeteries or on park benches - first in longhand, latterly on a MacBook Air laptop. He spent a couple of those years in Barcelona and in Paris, wandering and writing in different corners of the city each day. What started as a necessity - he did not have a study or a desk - became a habit and then a virtue. 'The routes I took were always very arbitrary, but I also knew that whichever way I went I would write something different in each place I ended up, simply because of what was around me.'

The result of this restless composition is, perhaps not surprisingly, a digressive 710-page comic yarn, which could be read as a Great Australian Novel. Toltz's book is ostensibly a father-and-son narrative, the would-be mentor and the resistant protege, but that description doesn't quite capture its tone or its ambition. It is, rather, a sort of freewheeling examination of the interior life of that curious animal, the white Australian male.

It is by turns a prison diary - Jasper Dean, the son, is trying to make sense of his life from behind bars (including the four years he spent in a coma from which he remembers everything said at his bedside) - and an eccentric political manifesto. Martin Dean, the father, running on a platform of making every Australian a millionaire, briefly finds himself in power and legislating that 'any politician breaking just one election promise would be punished in a back alley by a guy named Bruiser; every healthy person would have to look after at least one sick person'. Martin becomes the most hated man in Australia, just as his brother Terry, who murdered the Aussie cricket captain and went on the run - it's a long story - is the most loved.

Speaking last week in London, Toltz is cheerfully unrepentant about his wild and whirling book. 'I know you're supposed to hide your influences, but I suppose I see writing as riffing, really, about whatever you have been reading or thinking about that day or that week.' The things he read most of were Celine, Raymond Chandler, Thomas Bernhard and Knut Hansen. If you squint a bit between the lines, you can catch a glimpse of all of them. 'I am,' he says, 'influenced by books which don't have their eye on the endgame, but which try to be entertaining on each and every page.' No paragraph in A Fraction of the Whole is ever stuck for a one-liner: 'Amen is like the send button on an email,' Toltz writes, or: 'I instantly formed a love-hate relationship with my former self. I loved me for moving so optimistically towards the future and hated me for getting there and fucking it up.'

For a while, that latter observation might have described his own life. The compulsive nature of the novel was partly born out of desperation. It seems odd now, Toltz says, at 34, to see himself described, as he has been, as the wunderkind of Australian fiction: 'The pressure I had from being in my thirties and completely kind of failing at everything I had tried to do meant this book had all my hopes and dreams riding on it. I mean, it comes to sound a bit ridiculous to describe yourself as a writer when you have nothing in print. Also, I'd got to the point where I felt I needed some practical improvements in my life, like money.'

He'd always wanted to avoid having a fall-back career so he'd supported his writing by teaching English, or working in telesales or as an extra in films (hospital dramas mostly - lying like a patient etherised on a table). All first novels are a triumph of optimism over realism, but this one feels even more like that than most. Toltz never showed it to anyone before he sent it out to publishers; it was a private obsession that kept on growing. 'Strangely,' he says, 'it started out as two short stories, ones that I had entered, unsuccessfully, for various competitions. I liked the opening of one and the ending of the other. I just thought, "I'll fill in the middle, that won't take long."'

It is tempting to imagine autobiography in the father and son, but Toltz denies any similarity. His parents were both lawyers and, if pressed, he sees more of himself in the eccentric father-figure than in the mixed-up son. The book feels a little like a wayward surrogate child, though. He talks about it in those terms too. 'When people come up to me and say, "I read your book", I'm thinking, "How dare you! Who gave you a copy?" We spent so long together, just the two of us...'

Now that his novel has a life of its own, he says, 'there are things that I want for the book that I don't really want for myself'. One of those things is the weirdness that may come with winning the Booker Prize. 'I'm not going there in my mind,' Toltz insists. 'At the moment, I'm thinking of it as shortlisted-plus-dinner. That's more than enough for me.'